article: When you read an article you will understand and remember it better if you can work out how the writer has put the ideas together.Sometimes a writer puts ideas together by asking questions and then answering them.For example,if the article is about groundhogs ,the set of questions in the writer's head might be:
  What does a groundhog look like?
  Where do groundhogs live?
  What do they eat?...
  In the article,the author might answer those questions.
  Sometimes an author writes out her questions in the article.These questions give you signals.They tell you what the author is going to write next.Often an author has a question in her head but she doesn't write it out for you.You have to work out her question for yourself.Here's a sample reading for you to practice this method.
  Earthworms
  Do you know how many kinds of earthworms there are?There are about 1800 kinds in the world! They can be brown,purple,green.They can be as small as 3 cm long and as large as 3 m long.
  The best time to see earthworms is at night,especially a cool,damp night.That's when they come up from their burrows to hunt for food.Earthworms don't like to be in the sun.That's because they breathe through their skin,and they can't breathe if their skin gets too dry.Earthworms must come out of the earth if it rains a lot,because they can't breathe in their flooded burrows.What a dangerous life!
  Earthworms don't have eyes,so how can they tell when it's dark? They have special places on their skin that are sensitive to light.These spots tell whether it's light or dark.If you shine a flashlight on an earthworm at night,it will quickly disappear into the ground.
  Earthworms don't have ears either,but they can hear by feeling movements in the earth.If you want to hear like an earthworm,lie on the ground with your fingers in your ears.Then have a friend stamp his or her feet near you.This is how earthworms feel birds and people walking,and moles digging,near them.
  Earthworms are useful.Farmers and gardeners like having lots of earthworms in their land because the worms help to make better soil when they dig.That digging keeps the soil loose and airy .In one year earthworms can pile up as much as 23,000 kg of castings in an area about the size of a football field.
question: What's the purpose of reading Earthworms?
options: To show the special life facts of earthworms. To explain the differences from the groundhogs. To put the writer's idea into real use. To make the readers think more clearly.